During the 10-month period of this supplement, we plan to conduct studies in speech production and speech perception similar to those presented in the original grant proposal. The overall objective of these studies is to gain an understanding of the relation between syntactic and phonetic coding in speech processing. Experiments on speech production are conducted to test how speakers' syntactic representation of an utterance constrains the phonetic representation of two prosodic variables, duration and fundamental frequency. In studies on perception, experiments are aimed at determining whether and how a listener utilizes information contained in the durational representation of speech segments and pauses to recover and predict syntactic relations in sentences. During the past two years, work on the project has focused on studies of speech production. The results of such studies have led to the development of a theory of syntactic-to-phonetic coding in speech production and have served to guide new work on speech preception. The studies to be conducted during the 10-month period of this supplement deal primarily with perception. Experiments will be conducted to examine whether listeners utilize variations in the duration of a vowel segment to recover and predict syntactic structure. The durational variations will be produced by electronically deleting or reduplicating individual glottal cycles during the steady state portion of a vowel segment from naturally spoken sentences.